JP2017529318A - Stabilization of tris (2-hydroxyethyl) methylammonium hydroxide against degradation by dialkylhydroxylamines - Google Patents

Abstract

The present invention relates to a stabilizing solution useful as a raw material in various applications and a method for stabilizing such aqueous solutions with stabilizers comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts. I will provide a. Stabilizing solutions and methods for stabilizing their aqueous solutions include, for example, aqueous solutions of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) and / or carbohydrazide (CHZ).

Description

  It is common to put many chemical components into a solution to form a raw material, which is then used in any of a variety of applications. However, when in solution form, sometimes the raw material tends to become unstable. Having an unstable raw material solution is undesirable because it can adversely affect various problems such as shorter shelf life, chemical degradation, and the effectiveness and performance of the raw material solution.

  For example, a solution of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) is used in a variety of applications, including a cleaning composition for use after chemical mechanical polishing (CMP) of a semiconductor wafer is performed. Raw material.

  In this regard, the semiconductor wafer is typically composed of a substrate on which a plurality of transistors are formed, such as a silicon wafer. The transistors are chemically and physically connected to the substrate and interconnected through the use of well-known multi-level coplanar interconnects to form functional circuits. Typical multi-level interconnects include, for example, one or more of the following: titanium (Ti), titanium nitride (TiN), copper (Cu), aluminum (Al), tungsten (W), tantalum (Ta) ) Or an arbitrary combination thereof.

  Traditional techniques for forming functional multi-level coplanar interconnects have included planarizing the surface of the interconnect through chemical mechanical polishing (CMP). CMP involves simultaneously polishing the upper first layer chemically and mechanically to expose the surface of the non-planar second layer on which the first layer is formed (eg, US Pat. Nos. 4667151, 4910155, 4944836, 6592776, 7524347, and 8518135).

  A cleaning composition is used because the CMP process tends to leave undesirable contaminants on the wafer surface. In particular, the non-metallic substrate (eg, silicon dioxide) of a polished wafer often comes from the remainder of the polishing composition, eg, silica or alumina abrasive particles, and from the polishing composition and from the material to be polished. Contaminated with metal ions. Such contaminants can adversely affect the performance of the semiconductor wafer. As a result, after the polishing composition has been applied to the semiconductor surface, the polishing composition is typically cleaned from the wafer surface with an aqueous cleaning solution after CMP is complete (eg, US Pat. Nos. 4,051,057, 5,334,332). Nos. 5837666, 5981454, 6395693, and 6541434, and US Patent Application Publication No. 2009/0130849).

  However, THEMAH, which can be used as a base in post-CMP cleaning compositions, is susceptible to oxidative degradation. This oxidative degradation is indicated by changes to the physical and chemical properties of the composition. Such changes include discoloration, the appearance of bubbles through gas generation (gassing), and / or negative pH drifting. These changes may occur for example during ambient conditions, especially during storage. The rate of decomposition may increase at elevated temperatures.

  Typically, oxygen is removed from the vessel with a stream of nitrogen gas to protect the solution against oxidative degradation. This method slows the process of decomposition, and the presence of dissolved oxygen in the aqueous solution ultimately negates it. Alternatively, stabilizers can be added to chemically prevent oxidative degradation. For example, THEMAH is typically supplied with monomethyl ether of hydroquinone (MEHQ), a few hundred ppm of free radical scavenger, but MEHQ has limited water solubility and is ineffective at low densities. In addition, the presence of additional organic components can affect the performance of the solution (eg, post-CMP cleaning composition).

  Accordingly, there is a need for methods for stabilizing aqueous solutions containing THEMAH or other compounds, and related stabilizing solutions.

  In one aspect, the present invention provides a method for stabilizing an aqueous solution of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH). The method comprises adding, consisting of, or consisting essentially of a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts to an aqueous solution of THEMAH.

  In another aspect, the present invention provides a stabilized THEMAH solution. The solution comprises, consists of, or consists essentially of THEMAH, water and a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts.

  In another aspect, the present invention provides a method for stabilizing an aqueous solution of carbohydrazide (CHZ). The method comprises adding, consisting of, or consisting essentially of a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts to an aqueous solution of CHZ.

  In another aspect, the present invention provides a stabilized CHZ solution. The solution comprises, consists of, or consists essentially of CHZ, water, and a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts.

Without wishing to be bound by any particular theory, it is a schematic depiction illustrating the process of biooxidative degradation of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH). Copper loss (unit: angstrom) (y-axis) versus time (unit: seconds) (x-axis) of two cleaning compositions, one containing diethylhydroxylamine (DEHA) and the other not containing diethylhydroxylamine (DEHA) ), And the two compositions were applied to copper coupons (4.1 cm × 4.1 cm), once prepared and once after 4 months, as described in Example 2. Applied twice.

  Embodiments of the present invention provide stabilizing solutions useful as raw materials in various applications, and methods for stabilizing such aqueous solutions. Stabilizing solutions and methods for stabilizing their aqueous solutions include, for example, solutions of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) and / or carbohydrazide (CHZ).

  In particular, it has been found that stabilizers comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts can advantageously be added to an aqueous solution of THEMAH and / or CHZ. The inorganic or organic salt can be one or more of nitrate, phosphate, acetate, sulfate, hydrochloride, lactate, and glycolate. In a preferred embodiment, the dialkylhydroxylamine is diethylhydroxylamine (DEHA). For ease of discussion, DEHA is sometimes a stabilizer referred to below, but that discussion applies to any other stabilizer mentioned above unless otherwise indicated. I want you to understand.

Application to Raw Material Embodiments of the present invention can be used in any suitable application. One such example is a cleaning composition that is used to remove some or all contaminants after chemical mechanical polishing (CMP) is performed on a substrate. Such embodiments that use stabilizing ingredients (ie, solutions) as cleaning compositions have applicability to a wide variety of semiconductor wafers used in the fabrication of integrated circuits and other microdevices. A semiconductor wafer typically includes an insulator and a conductive agent. Stabilizing raw materials according to embodiments of the present invention can be used to clean substrates containing various such insulators and conductive agents.

  For example, with some applications in accordance with embodiments of the present invention, copper can be a suitable conductive agent and silicon oxide (eg, carbon doped) can be used as an insulator. Other layers may be titanium nitride, tantalum nitride, or reactive metals to facilitate the interaction between copper and, for example, silicon dioxide or other materials that have a relatively low dielectric constant relative to other materials. (E.g., cobalt metal). It should be understood that the layers can be applied (applied) by any suitable method, such as chemical vapor deposition (CVD). After CMP, using a stabilized cleaning composition prepared in accordance with embodiments of the present invention may promote conductivity by removing contaminants that otherwise interfere with and interfere with conductivity. desirable.

  Although conventional CMP processes are suitable for polishing, they tend to leave undesirable contaminants on the wafer surface. The balance from the polishing composition and process consists of organic compounds such as benzotriazole (BTA), silica, or other abrasive particles, surfactants, metal ions, polishing pad wear powder (debris), CMP byproducts (eg, In some cases, fragments (debris) that may exist in the form of a metal addition ion having an organic ligand) may be generated. The stabilization embodiments of the present invention may be suitable for removing these undesirable contaminants.

Stabilizers In accordance with embodiments of the present invention, the feedstock is stabilized with one or more dialkylhydroxylamines or their inorganic or organic acid salts, such as DEHA. Such dialkylhydroxylamines or their inorganic or organic acid salts surprisingly and surprisingly provide a stabilizing effect in the solution of the raw material, whereby in some embodiments their Extend shelf life. In some embodiments, as compared to a solution of a raw material without DEHA or such a solution with a small amount of DEHA, it can be understood that, for example, the raw material, For example, DEHA has been found to exhibit a stabilizing effect in particular to greatly reduce the decomposition of THEMAH.

  This stabilizing effect can be understood in various applications, such as post-CMP cleaning, photoresist removal, and / or raw chemical manufacturing and storage. In some embodiments of the present invention where a stabilizing ingredient (ie, solution) is used as a cleaning composition, DEHA can be used, for example, as an organic inhibitor in the cleaning composition, which is desirably Improve corrosion resistance and / or eliminate active oxygen from transition metal surfaces.

  The DEHA can be present in any suitable amount in the raw solution. In some embodiments, the DEHA is about 0.002 wt% to about 10 wt%, such as about 0.003 wt% to about 5 wt%, such as about 0.003 wt% to about 4 wt%, about 0.005 wt% to about It can be present in an amount of 5 wt%, about 0.2 wt% to about 4 wt%, about 1 wt% to about 3.5 wt%, or about 2 wt% to about 3 wt%. For example, in some embodiments, DEHA is in an amount from about 0.001 wt% to about 0.2 wt% (0.002 wt% to about 0.06 wt%) when in diluted form. Additionally, in some embodiments, DEHA is in an amount of about 0.05 wt% to about 20 wt% (eg, about 0.1 wt% to about 10 wt%) when in concentrated form.

  In some embodiments comprising DEHA as a stabilizer, DEHA is in a diluted form from about 0.001 wt% to about 0.2 wt%, such as from about 0.001 wt% to about 0.01 wt%, about 0.001 wt%. % To about 0.02 wt%, about 0.001 wt% to about 0.03 wt%, about 0.001 wt% to about 0.04 wt%, about 0.001 wt% to about 0.05 wt%, about 0.001 wt% About 0.06 wt%, about 0.001 wt% to about 0.08 wt%, about 0.001 wt% to about 0.1 wt%, about 0.001 wt% to about 0.12 wt%, about 0.001 wt% to about 0 .14 wt%, about 0.001 wt% to about 0.16 wt%, about 0.001 wt% to about 0.18 wt%, about 0.002 wt% to about 0.01 wt%, about 0.002 wt% to about 0.02 wt %, About 0.002 wt About 0.03 wt%, about 0.002 wt% to about 0.04 wt%, about 0.002 wt% to about 0.05 wt%, about 0.002 wt% to about 0.06 wt%, about 0.002 wt% to about 0.08 wt%, about 0.002 wt% to about 0.1 wt%, about 0.002 wt% to about 0.12 wt%, about 0.002 wt% to about 0.14 wt%, about 0.002 wt% to about 0. 16 wt%, about 0.002 wt% to about 0.18 wt%, about 0.002 wt% to about 0.2 wt%, about 0.003 wt% to about 0.02 wt%, about 0.003 wt% to about 0.03 wt% About 0.003 wt% to about 0.04 wt%, about 0.003 wt% to about 0.05 wt%, about 0.003 wt% to about 0.06 wt%, about 0.003 wt% to about 0.08 wt%, about 0.003 wt% to about 0.1 wt%, about 0 003 wt% to about 0.12 wt%, about 0.003 wt% to about 0.14 wt%, about 0.003 wt% to about 0.16 wt%, about 0.003 wt% to about 0.18 wt%, about 0.003 wt% About 0.2 wt%, about 0.005 wt% to about 0.01 wt%, about 0.005 wt% to about 0.02 wt%, about 0.005 wt% to about 0.03 wt%, about 0.005 wt% to about 0.04 wt%, about 0.005 wt% to about 0.05 wt%, about 0.005 wt% to about 0.06 wt%, about 0.005 wt% to about 0.08 wt%, about 0.005 wt% to about 0.0. 1 wt%, about 0.005 wt% to about 0.12 wt%, about 0.005 wt% to about 0.14 wt%, about 0.005 wt% to about 0.16 wt%, about 0.005 wt% to about 0.18 wt% Or about 0.005 wt% to about 0. It is present in an amount that is 2 wt%.

  In some embodiments comprising DEHA as a stabilizer, DEHA is in a concentrated form from about 0.05 wt% to about 20 wt%, such as from 0.05 wt% to about 0.5 wt%, from about 0.05 wt% to about 1 wt%, about 0.05 wt% to about 2 wt%, about 0.05 wt% to about 4 wt%, about 0.05 wt% to about 8 wt%, about 0.05 wt% to about 12 wt%, about 0.05 wt% to about 16 wt%, about 0.1 wt% to about 0.5 wt%, about 0.1 wt% to about 1 wt%, about 0.1 wt% to about 2 wt%, about 0.1 wt% to about 4 wt%, 0.1 wt% to About 8 wt%, about 0.1 wt% to about 12 wt%, about 0.1 wt% to about 16 wt%, about 0.1 wt% to about 20 wt%, about 0.5 wt% to about 1 wt%, about 0.5 wt% About 2 wt%, about 0.5 wt% to about 4 wt%, about 0.5 wt% to about wt%, about 0.5 wt% to about 12 wt%, about 0.5 wt% to about 16 wt%, about 0.5 wt% to about 20 wt%, about 1 wt% to about 2 wt%, about 1 wt% to about 4 wt%, about 1 wt% to about 12 wt%, about 1 wt% to about 16 wt%, about 1 wt% to about 20 wt%, about 2 wt% to about 4 wt%, 2 wt% to about 8 wt%, about 2 wt% to about 12 wt%, about 2 wt% to It is present in an amount that is about 16 wt%, or about 2 wt% to about 20 wt%.

  In general, the actual amount of one or more components in a stabilizing solution useful as a raw material for various applications, and such aqueous solutions prepared according to embodiments of the present invention (eg, THEMAH, CHZ, And / or it is understood that the method for stabilizing one or more dialkylhydroxylamines or their inorganic or organic acid salts (eg DEHA) can be varied depending on the degree of dilution or concentration desired. I want to be. In this regard, some embodiments can be packaged (concentrated) in the form of a concentrate, with water added later to dilute the solution, eg, at the point of use (eg, by the end user). Alternatively, the solution can be packaged in diluted form with water already contained. For example, in some embodiments, concentrated forms and / or solutions of each component can generally facilitate transport, distribution, and sale. However, in other embodiments, each component and / or solution can generally be in a diluted form, for example, to simplify final use. Thus, mass ranges as described herein and throughout the components described above may refer to either a diluted or concentrated range.

  Thus, each component, such as DEHA, is diluted or concentrated for final use and then concentrated and then diluted (eg, 2 ×, 5 ×, 10 ×, 25 × relative to the diluted form). , 40 times, 50 times, 60 times, 70 times, 100 times, 125 times, 150 times, 175 times, 200 times, etc.). The concentrate contains equal volumes of water (eg, 1 equivalent volume of water, 4 equivalent volumes of water, 9 equivalent volumes of water, 24 equivalent volumes of water, 39 equivalent volumes of water, 49 equivalent volumes of water, 59 Each component when diluted with equal volume water, 69 equal volume water, 99 equal volume water, 124 equal volume water, 149 equal volume water, 174 equal volume water, or 199 equal volume water) Is present in an embodiment of the present invention in an amount within the dilution range described below for each component. Further, as will be appreciated by those skilled in the art, the concentrate can contain an appropriate amount of water present in the final solution. For example, in some applications, such as cleaning compositions, the concentrate can produce low final metal surface roughness and corrosion, and / or contaminants (eg, abrasive particles, metal ions, and A final wash to ensure that the compound or compounds that improve the efficient removal of the other residues discussed in 1) are at least partially or fully diluted in the concentrate. An appropriate amount of water present in the composition can be included.

THEMAH Stabilizing Solutions and Methods for Stabilizing Those Solutions DEHA can be used, for example, to stabilize THEMAH, a base used in various applications, for example, cleaning compositions. THEMAH is desirably used in cleaning compositions because it is a readily available raw material and is known to have chelating performance. In the cleaning composition, THEMAH, quaternary ammonium hydroxide, can be used as a bulky protective ligand, which produces a low final metal surface roughness and / or the balance of the polishing composition. (Eg, silica or alumina abrasives), metal ions from the polishing composition and from the material to be polished, polishing pad wear powder, CMP by-products, surfactants, and other residues (eg, BTA) It is desirable to efficiently remove contaminants including organic residues). THEMAH can be used alone or in combination with other bulky protective ligands. Although not wishing to be bound by any particular theory, it is believed that DEHA can prevent oxidative degradation in THEMAH. For example, according to embodiments of the present invention, DEHA has been found to prevent negative pH drift in solutions containing THEMAH.

  In embodiments where THEMAH is used as a raw material to be stabilized, it can be present in any suitable amount. For example, THEMAH is about 0.01 wt% to about 48 wt%, such as about 0.2 wt% to about 35 wt%, such as about 1 wt% to about 25 wt%, about 1.5 wt% to about 15 wt%, about 2 wt%. Can be present in an amount of about 10 wt%, about 2.5 wt% to about 7 wt%, or about 3 wt% to about 6 wt%. For example, in some embodiments, THEMAH is in an amount of about 0.01 wt% to about 0.8 wt% when in diluted form. Additionally, in some embodiments, THEMAH is in an amount of about 1 wt% to about 30 wt% when in concentrated form.

  In some embodiments using THEMAH as a raw material to be stabilized, THEMAH is in a diluted form from about 0.01 wt% to about 0.8 wt%, such as from about 0.01 wt% to about 0.3 wt%. About 0.01 wt% to about 0.5 wt%, about 0.05 wt% to about 0.3 wt%, about 0.05 wt% to about 0.8 wt%, about 0.1 wt% to about 0.3 wt%, about 0.1 wt% to about 0.5 wt%, about 0.1 wt% to about 0.8 wt%, about 0.2 wt% to about 0.3 wt%, about 0.2 wt% to about 0.5 wt%, or about 0 Present in an amount that is from 2 wt% to about 0.8 wt%.

  In some embodiments using THEMAH as a raw material to be stabilized, THEMAH is in a concentrated form from about 1 wt% to about 30 wt%, such as from about 1 wt% to about 10 wt%, from about 1 wt% to about 15 wt%. About 1 wt% to about 20 wt%, about 1 wt% to about 25 wt%, about 3 wt% to about 10 wt%, about 3 wt% to about 15 wt%, about 3 wt% to about 20 wt%, about 3 wt% to about 25 wt%, about 3 wt% to about 30 wt%, about 5 wt% to about 10 wt%, about 5 wt% to about 15 wt%, about 5 wt% to about 20 wt%, about 5 wt% to about 25 wt%, about 5 wt% to about 30 wt%, about 7 wt% Present in an amount that is about 10 wt%, about 7 wt% to about 15 wt%, about 7 wt% to about 20 wt%, about 7 wt% to about 25 wt%, or about 7 wt% to about 30 wt%.

Stabilized solutions of CHZ and methods for stabilizing those solutions DEHA is used to stabilize, for example, CHZ, antioxidant oxygen scavengers used in various applications, eg cleaning compositions can do. CHZ can be used alone or in combination with other bulky protective ligands (eg, THEMAH). While not wishing to be bound by any particular theory, it is believed that DEHA can prevent oxidative degradation in CHZ. For example, in accordance with an embodiment of the present invention, DEHA has been found to prevent discoloration signifying oxidation and formation of bubbles in a solution containing CHZ.

  In some embodiments using CHZ as a raw material to be stabilized, CHZ is from about 0.01 wt% to about 18.0 wt%, such as from about 0.02 wt% to about 12 wt%, such as about 0.0. It can be present in an amount from 05 wt% to about 6 wt%, from about 0.1 wt% to about 4 wt%, from about 1 wt% to about 3.5 wt%, or from about 2 wt% to about 3 wt%. For example, in some embodiments, CHZ is in an amount from about 0.01 wt% to about 0.04 wt% when in diluted form. Additionally, in some embodiments, CHZ is in an amount from about 0.5 wt% to about 12 wt% when in concentrated form.

  In some embodiments using CHZ as a raw material to be stabilized, CHZ is in diluted form from about 0.01 wt% to about 0.04 wt%, such as from about 0.01 wt% to about 0.02 wt%. About 0.01 wt% to about 0.03 wt%, about 0.02 wt% to about 0.03 wt%, about 0.02 wt% to about 0.04 wt%, or about 0.03 wt% to about 0.04 wt% Present in a certain amount.

  In some embodiments using CHZ as a raw material to be stabilized, CHZ is in a concentrated form from about 0.5 wt% to about 12 wt%, such as from about 0.5 wt% to about 3 wt%, about 0.0. 5 wt% to about 5 wt%, about 0.5 wt% to about 8 wt%, about 0.5 wt% to about 10 wt%, about 1 wt% to about 3 wt%, about 1 wt% to about 5 wt%, about 1 wt% to about 8 wt% About 1 wt% to about 10 wt%, about 1 wt% to about 12 wt%, about 2 wt% to about 3 wt%, about 2 wt% to about 5 wt%, about 2 wt% to about 8 wt%, about 2 wt% to about 10 wt%, or It is present in an amount that is about 2 wt% to about 12 wt%.

  CHZ can be stabilized either alone or with THEMAH. As such, the above weight percentages apply to solutions of CHZ with or without THEMAH or other raw active ingredients.

Mass ratio Stabilizers can be provided in any suitable mass ratio with the active ingredients of the raw material to be stabilized. To illustrate, suitable mass ratios of stabilizer to active ingredient can be understood from the mass ratios provided below relative to the THEMAH: DEHA and CHZ: DEHA ratios provided below. However, it should be understood that similar ratios can be readily applied to other ingredient active ingredient and stabilizer combinations in accordance with embodiments of the present invention.

  In some embodiments, the mass ratio of THEMAH: DEHA is about 0.5: 1 to about 50: 1, such as about 0.5: 1 to about 40: 1, such as about 0.5: 1. About 33: 1, about 0.5: 1 to about 30: 1, about 0.5: 1 to about 25: 1, about 0.5: 1 to about 20: 1, about 0.5: 1 to about 15 : 1, about 0.5: 1 to about 10: 1, about 0.5: 1 to about 8: 1, about 0.5: 1 to about 6: 1, about 0.5: 1 to about 5: 1 About 0.5: 1 to about 4.5: 1, about 0.5: 1 to about 4: 1, about 0.5: 1 to about 3: 1, about 0.5: 1 to about 2: 1 About 0.5: 1 to about 1: 1, about 0.5: 1 to about 1: 1, about 1: 1 to about 50: 1, about 1: 1 to about 40: 1, about 1: 1 to About 33: 1, about 1: 1 to about 30: 1, about 1: 1 to about 25: 1, about 1: 1 to about 20: 1, about 1: 1 to about 15: 1, about 1: 1 About 10: 1, about 1: 1 to about 8: 1, about 1: 1 to about 6: 1, about 1: 1 to about 5: 1, about 1: 1 to about 4.5: 1, about 1: 1 to about 4: 1, about 1: 1 to about 3: 1, about 1: 1 to about 2: 1, about 1: 1 to about 1.7: 1, about 1.7: 1 to about 50: 1 About 1.7: 1 to about 40: 1, about 1.7: 1 to about 33: 1, about 1.7: 1 to about 30: 1, about 1.7: 1 to about 25: 1, about 1.7: 1 to about 20: 1, about 1.7: 1 to about 15: 1, about 1.7: 1 to about 10: 1, about 1.7: 1 to about 8: 1, about 1. 7: 1 to about 6: 1, about 1.7: 1 to about 5: 1, about 1.7: 1 to about 4.5: 1, about 1.7: 1 to about 4: 1, about 1. 7: 1 to about 3: 1, about 1.7: 1 to about 2: 1, about 3: 1 to about 50: 1, about 3: 1 to about 40: 1, about 3: 1 to about 33: 1 About 3: 1 to about 30: 1, about 3: 1 to about 25 1, about 3: 1 to about 20: 1, about 3: 1 to about 15: 1, about 3: 1 to about 10: 1, about 3: 1 to about 9: 1, about 3: 1 to about 8: 1, about 3: 1 to about 7: 1, about 3: 1 to about 6: 1, about 3: 1 to about 5: 1, about 3: 1 to about 4.5: 1, about 3: 1 to about It can be 4: 1, or about 3: 1 to about 3.5: 1.

  In some embodiments, the mass ratio of CHZ: DEHA is about 3: 1 to about 10: 1, such as about 3: 1 to about 9: 1, such as about 3: 1 to about 8: 1, about 3: 1 to about 7: 1, about 3: 1 to about 6: 1, about 3: 1 to about 5: 1, about 3: 1 to about 4: 1, about 3: 1 to about 3.5: 1 About 3.5: 1 to about 10: 1, about 3.5: 1 to about 9: 1, such as about 3.5: 1 to about 8: 1, about 3.5: 1 to about 7: 1. About 3.5: 1 to about 6: 1, about 3.5: 1 to about 5: 1, about 3.5: 1 to about 4: 1, about 4: 1 to about 10: 1, about 4: 1 to about 9: 1, about 4: 1 to about 8: 1, about 4: 1 to about 7: 1, about 4: 1 to about 9: 1, about 4: 1 to about 8: 1, about 4: 1 to about 7: 1, about 4: 1 to about 6: 1, or about 4: 1 to about 5: 1.

Water The stabilization solution of the present invention contains water, which can be present in any suitable amount. For example, water can be used for a suitable application, for example, from about 50.0 wt% to about 5 wt%, based on the total weight of the stabilizing solution, to clean the substrate after CMP has been performed. Stabilized in an amount of 99.99 wt%, for example, about 50 wt% to about 40 wt%, about 40 wt% to about 5 wt%, about 5 wt% to about 0.1 wt%, or about 0.1 wt% to about 0.01 wt% It can be present in solution.

  In a concentrated form of the stabilizing solution, a specific amount of water is, for example, about 45 wt% to about 99 wt%, such as about 50 wt% to about 95 wt%, about 60 wt% to about 90 wt%, about 70 wt% to about 85 wt%, Alternatively, it can be included in the stabilization solution of some embodiments of the present invention in an amount of about 75 wt% to about 80 wt%.

Properties Surprisingly and surprisingly, embodiments of the present invention provide a stabilized solution of raw material that has a relatively long shelf life and prevents oxidative degradation. For example, in various embodiments, the stabilization solution of the present invention can be physically and chemically properties such as discoloration, bubble appearance through gas evolution, and / or negative, for example, at ambient or even elevated temperatures. Withstands changes in pH drift.

  In some embodiments, the stabilizing solution of the present invention is at least about 1 month, such as at least about 2 months or more, such as at least about 3 months or more, at least about 4 months or more, at least about 5 months or more, at least about 6 months or more, at least about 7 months or more, at least about 8 months or more, at least about 9 months or more, at least about 10 months or more, at least about 11 months or more, at least about 12 months or more, at least about 13 months or more, at least about 14 months At least about 15 months or more, at least about 16 months or more, at least about 17 months or more, at least about 18 months or more, at least about 19 months or more, at least about 20 months or more, at least about 21 months or more, at least about 22 months or more, Stable for at least about 23 months or more, or at least about 24 months or more.

  Surprisingly and surprisingly, some embodiments of the present invention are also desirable to prevent negative pH drift. In this regard, negative pH drift indicates degradation that adversely affects the base concentration of the solution. For example, some embodiments have about 0.5 or less, such as about 0.45 or less, such as about 0.4 or less, about 0.35 or less, about 0.3 or less, about 0.25 or less, about Has a pH drift of 0.2 or less, about 0.15 or less, about 0.1 or less, about 0.05 or less, about 0.01 or less or no pH drift.

Nitrogen protection In some embodiments, surprisingly and surprisingly, adding nitrogen protection has a beneficial effect on the length of stability in relation to the amount of stabilizer required in the solution. I knew that to give. Nitrogen protection was not known to be very effective in stabilizing THEMAH and / or CHZ solutions without the stabilizers of embodiments of the present invention. According to an embodiment of the present invention, the present invention provides that when a nitrogen protection is added in addition to a stabilizer in the form of a dialkylhydroxylamine, e.g. DEHA, a smaller amount of stabilizer is less protected without nitrogen protection. Is required to achieve a length of stability comparable to some solutions. In some embodiments, nitrogen protection in the form of nitrogen gas as a “pillow” or “blanket” in a container covering the stabilizing solution advantageously further and synergistically stabilizes the raw material solution.

Instability Process Attention is now directed to FIG. While not wishing to be bound by any particular theory, representations 1 through 3 illustrate processes that may be related to the instability of the THEMAH feedstock solution.

  Display 1 illustrates the THEMAH molecule. The THEMAH molecule comes into contact with Candida bacteria ("Candida B") and its possible effects are shown in Display 2. It is believed that common bacteria, such as Candida B, can oxidize —OH groups (x) through enzymatic action and convert them to aldehyde groups. Through the second enzymatic action, Candida B can further cleave the bond between nitrogen and the aldehyde group, which is further thought to oxidize the aldehyde group as shown in Display 3. Thus, the THEMAH molecule becomes an uncharged amine containing two non-base -H groups. The aldehyde group is thought to be converted to acetaldehyde, which immediately oxidizes to produce acetic acid with a high pH. Acetic acid reacts with the uncharged amine and neutralizes it to form a salt. One possible effect of such a reaction is a loss of basicity.

In some embodiments, the by-product of THEMAH degradation further reacts with CHZ, which is further believed to make the solution pink. Oxidative degradation of CHZ creates CO ₂ and N ₂ bubbles and lower concentrations of CHZ because large amounts of CHZ are decomposed to indicate oxidative degradation.

  To counter and overcome this instability, dialkylhydroxylamines, such as DEHA, or their inorganic or organic acid salts either capture activated oxygen or interfere with bacterial enzymes, This is believed to stabilize the solution containing THEMAH by preventing this oxidative degradation causing negative pH drift. While not wishing to be bound by any particular theory, for example, DEHA is a bacterium required for the oxidation of hydroxyalkyl (eg, hydroxyethyl) substituents in THEMAH to related aldehydes. It was believed that the enzyme could be prevented, and in some embodiments, DEHA was found to exhibit a stabilizing effect.

Methods of Cleaning Embodiments of the present invention used as a cleaning composition (ie, solution) for use after CMP has been performed can be applied in any suitable manner. For example, one such cleaning method includes (a) providing a semiconductor wafer having contaminants resulting from chemical mechanical polishing of the semiconductor wafer, and (b) the surface of the semiconductor wafer described herein. Contacting, and consisting of, consisting of, or consisting essentially of removing at least some of the contaminants from the surface of the semiconductor wafer. As indicated herein, contaminants can include, for example, abrasive particles, organic residues, metal ions, pad wear powder and CMP by-products, or any combination thereof. The wafer can include a low-k dielectric material and / or a metal conductor.

  Further, a method for polishing and cleaning a surface of a semiconductor wafer includes (a) providing a polishing pad, a chemical mechanical polishing composition, and a semiconductor wafer, and (b) converting the semiconductor wafer into a polishing pad and a polishing composition. And (c) moving the polishing pad relative to the surface of the semiconductor wafer along with the polishing composition, during which the surface of the semiconductor wafer is abraded so that the polishing surface of the wafer is removed from the chemical mechanical polishing composition. Polishing the surface of the wafer to contain contaminants; and (d) contacting the polishing surface of the semiconductor wafer containing contaminants with a cleaning composition as described herein to Removing, at least a portion of, contaminants from the polishing surface, consisting of, or consisting essentially of.

  Typically, a chemical mechanical polishing composition is utilized for polishing a semiconductor wafer using a polishing pad, and a method for polishing and cleaning a semiconductor wafer provides a chemical mechanical polishing composition between the polishing pad and the semiconductor wafer. And contacting the semiconductor wafer with the polishing composition with the polishing composition therebetween, and moving the polishing pad relative to the semiconductor wafer with the polishing composition between which the semiconductor wafer is abraded, thereby removing the semiconductor wafer. And further polishing. Embodiments of the present invention are not limited by the polishing composition, which can be any suitable polishing composition as known in the art. Additionally, embodiments of the present invention are not limited by the CMP apparatus and polishing pad used during polishing, which is any suitable CMP apparatus and polishing pad, many of which are known in the art. be able to.

  Generally, a chemical mechanical polishing apparatus includes: (a) a rotating platen; (b) a polishing pad disposed on the platen; and (c) a semiconductor wafer to be polished by contacting the rotating polishing pad. Holding the carrier. In some embodiments, the apparatus further includes (d) means for carrying the chemical mechanical polishing composition between the polishing pad and the semiconductor wafer. For example, the means for carrying the chemical mechanical polishing composition can include, for example, a pump and a flow measurement system.

  The following examples further illustrate the invention but, of course, should not be construed as any way of limiting its scope.

Example 1
This example illustrates the benefit of using a dialkylhydroxylamine, in this case diethylhydroxylamine (DEHA), in a post-CMP cleaning composition comprising tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) and carbohydrazide (CHZ). To demonstrate. Each sample was prepared in an amount of 3.5 liters in a 1 gallon (3.589 liter) plastic container. The aqueous solution contained 20 wt% THEMAH, 6 wt% CHZ, and 0.6 wt% to 6 wt% DEHA. The remaining 0.089 liter was filled with either oxygen or nitrogen, depending on the sample.

  Table 1 shows the effectiveness of DEHA as a stabilizer. Table 1 describes the wt% of DEHA added, whether nitrogen protection was added, the number of days the sample was observed, the appearance of the sample with respect to the level of discoloration and bubble appearance, and the change in pH. In Table 1, if it indicates nitrogen protection, it should be understood that nitrogen was added to replace oxygen.

  Any change in appearance or substantial pH drift indicated degradation of THEMAH base and CHZ. The THEMAH base and CHZ were stable when the pH drift was negligible, that is, 0.5 or less, and when the appearance of the sample did not change. Samples 1G, 1M, and 1N showed significant discoloration and accumulation of many bubbles and unacceptable negative pH drift. Samples 1A-1F, 1H-1L, and 1O-1R showed minimal or no discoloration, very little or no bubbles, and negligible negative pH drift.

Example 2
This example shows post CMP with tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) and carbohydrazide (CHZ) in terms of cleaning ability as measured by the amount of copper (copper loss) removed during post CMP cleaning. The benefits of using dialkylhydroxylamine, in this case diethylhydroxylamine (DEHA), in the cleaning composition are demonstrated. The more copper that is removed from the substrate to be polished by application of the cleaning solution, the more corroded the cleaning solution. Higher corrosivity may result in unnecessary defects on the substrate to be polished, including pit defects (ie, localized erosion), corrosion defects (ie, spread erosion), and higher roughness. is there.

  Post-CMP cleaning solutions for both samples were prepared with 5 wt% THEMAH, 2 wt% organic amine, monoethanolamine (MEA), and 1.5 wt% CHZ. Sample 2A contained 0.5 wt% DEHA, whereas sample 2B was prepared without DEHA. Nitrogen protection was added to both samples. The composition of each material is shown in Table 2 below.

  Samples 2A and 2B were tested by processing copper coupons (4.1 cm × 4.1 cm). For each sample, the amount of copper removed, measured in angstroms, relative to the time measured in seconds, was measured once at the time of preparation (“untreated”) and once after 4 months. . FIG. 2 illustrates the results of that test.

  As can be observed from FIG. 2, Samples 2A and 2B exhibited similar copper loss over 60 seconds when tested during the preparation of the cleaning solution. However, when measured a second time after 4 months, Sample 2A with DEHA showed much less copper loss than Sample 2B without DEHA. In fact, Sample 2A showed little change in performance after 4 months.

  All references, including publications, patent applications, and patents cited herein, are incorporated herein by reference, with each reference individually and specifically shown and described herein in its entirety. To the same extent as is incorporated herein by reference.

  Within the scope of describing the invention (especially within the scope of the following claims) "one (a)", "one", "the", and "at least one" The use of the term “at least one” as well as similar directives should be understood to encompass both the singular and the plural unless otherwise indicated herein or otherwise clearly contradicted by context. is there. Subsequent to the use of the term “at least one”, the description of one or more items (eg, at least one of A and B) is not expressly stated herein or expressly denied by context. Unless otherwise stated, it should be understood to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B). The terms “comprising”, “having”, “including” and “containing” are intended to be open-ended terms (ie, “including but not limited to”) unless otherwise specified. It should be understood as "not". The recitation of value ranges herein is intended to serve as a shorthand for referring individually to each independent value falling within the range, unless otherwise indicated herein. And each independent value is incorporated herein as if it were individually listed herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary terms provided herein (eg, “such as”) is intended solely to make the present invention more clear, Unless otherwise stated in the claims, it is not intended to limit the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations on those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect that those skilled in the art will make appropriate use of such variations, and that the inventors will implement the invention in a manner different from that specifically described herein. Intended. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims (42)

  A method for stabilizing an aqueous solution of tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) comprising a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts, Adding to an aqueous solution of THEMAH.   The method of claim 1, wherein the dialkylhydroxylamine is diethylhydroxylamine (DEHA).   3. The method of claim 2, wherein the THEMAH: DEHA mass ratio is about 0.5: 1 to about 50: 1.   3. The method of claim 2, wherein the THEMAH: DEHA mass ratio is about 1: 1 to about 33: 1.   3. The method of claim 2, wherein the THEMAH: DEHA mass ratio is from about 1.7: 1 to about 25: 1.   The method of claim 2, wherein the THEMAH: DEHA mass ratio is from about 3: 1 to about 10: 1.   The inorganic or organic salt is one or more of nitrate, phosphate, acetate, sulfate, hydrochloride, lactate, and glycolate, according to any one of claims 1 to 6. the method of.   8. The method of any one of claims 1-7, wherein the amount of THEMAH is from about 0.01 wt% to about 48 wt%.   9. The method of any one of claims 1-8, wherein the amount of DEHA is from about 0.003 wt% to about 5 wt%.   The method according to claim 1, wherein the solution further comprises carbohydrazide (CHZ).   The method of claim 10, wherein the amount of CHZ is from about 0.02 wt% to about 12 wt%.   12. A method according to any one of the preceding claims, wherein the solution has a pH drift of about 0.5 or less.   13. A method according to any one of claims 1 to 12, wherein the solution is stable for about 4 months or more.   14. The method of claim 13, wherein the solution is stable for about 6 months or more. A stabilized tris (2-hydroxyethyl) methylammonium hydroxide (THEMAH) solution comprising:
THEMAH,
water and,
A stabilizing solution comprising a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts.   16. The stabilizing solution according to claim 15, wherein the dialkylhydroxylamine is diethylhydroxylamine (DEHA).   17. The stabilizing solution of claim 16, wherein the THEMAH: DEHA mass ratio is about 0.5: 1 to about 50: 1.   17. The stabilizing solution of claim 16, wherein the THEMAH: DEHA mass ratio is about 1: 1 to about 33: 1.   17. The stabilizing solution of claim 16, wherein the THEMAH: DEHA mass ratio is from about 1.7: 1 to about 25: 1.   17. The stabilizing solution of claim 16, wherein the THEMAH: DEHA mass ratio is about 3: 1 to about 10: 1.   21. The any one of claims 15-20, wherein the inorganic or organic salt is one or more of nitrate, phosphate, acetate, sulfate, hydrochloride, lactate and glycolate. Stabilizing solution.   The stabilizing solution according to any one of claims 15 to 21, wherein the amount of THEMAH is from about 0.01 wt% to about 48 wt%.   23. The stabilization solution of any one of claims 15-22, wherein the amount of DEHA is from about 0.003 wt% to about 5 wt%.   24. The stabilizing solution according to any one of claims 15 to 23, wherein the solution further comprises carbohydrazide (CHZ).   25. The stabilization solution of claim 24, wherein the amount of CHZ is from about 0.02 wt% to about 12 wt%.   26. A stabilizing solution according to any one of claims 15 to 25, wherein the solution has a pH drift of about 0.5 or less.   27. A stabilizing solution according to any one of claims 15 to 26, wherein the solution is stable for about 4 months or more.   28. The stabilization solution of claim 27, wherein the solution is stable for about 6 months or more.   A method for stabilizing an aqueous solution of carbohydrazide (CHZ), comprising the step of adding a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts to the aqueous solution of CHZ. Method.   30. The method of claim 29, wherein the dialkylhydroxylamine is diethylhydroxylamine (DEHA).   30. The method of claim 29, wherein the CHZ: DEHA mass ratio is from about 3: 1 to about 10: 1.   The inorganic or organic acid salt according to any one of claims 29 to 31, wherein the inorganic or organic acid salt is one or more of nitrate, phosphate, acetate, sulfate, hydrochloride, lactate, and glycolate. The method described.   33. The method of any one of claims 29-32, wherein the amount of DEHA is from about 0.003 wt% to about 4 wt% and the amount of CHZ is from about 0.02 wt% to about 12 wt%.   34. The method of any one of claims 29 to 33, wherein the solution has a pH drift of about 0.3 or less.   35. The method of any one of claims 29 to 34, wherein the solution is stable for about 4 months or more. A stabilized carbohydrazide (CHZ) solution comprising:
CHZ,
water and,
A stabilizing solution comprising a stabilizer comprising one or more dialkylhydroxylamines or their inorganic or organic acid salts.   The stabilizing solution of claim 36, wherein the dialkylhydroxylamine is diethylhydroxylamine (DEHA).   38. The stabilization solution of claim 36, wherein the CHZ: DEHA mass ratio is from about 3: 1 to about 10: 1.   39. The method according to any one of claims 36 to 38, wherein the inorganic or organic acid salt is one or more of nitrate, phosphate, acetate, sulfate, hydrochloride, lactate, and glycolate. The stabilizing solution as described.   40. The stabilization solution of any one of claims 36 to 39, wherein the amount of DEHA is from about 0.003 wt% to about 4 wt% and the amount of CHZ is from about 0.02 wt% to about 12 wt%.   41. The stabilizing solution of any one of claims 36-40, wherein the solution has a pH drift of about 0.3 or less.   42. The stabilization solution of any one of claims 36 to 41, wherein the solution is stable for about 4 months or more.

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